The Money Pit

I am contemplating wider wheels, and would like to keep the 15 inch diameter. Currently I have 15x9 Welds with 295/55 drag radials, and on the 9 inch wheels, the tire is pinched slightly, hence my desire to run wider wheels. The issue I am trying to overcome is the fact the tire already extends beyond the fender an inch, so the prospect of just going wider all on the outside, is something I'd rather not do. If I split the difference,...add 1/2 inch more backset, and 1/2 inch outside, I end up with the tire essentially in the same place, but on a wider wheel. This would be ideal.


Here's the problem. The current wheel has only about 1/2 inch clearance to the spring end, so I know I can cut the spring. My question is how much spring bolt angle is too much. I have an idea to use a heim joint, and relocate the spring bolt if I must, but I was wondering what others have done in this situation.

The Money Pit

This is kind of what I had in mind to do.

resdoggie

If you want the extra 1/2" inwards, just add the 1/2" to the backspace of the wheel you are using now. Then get under the car and see if that extra inboard 1/2" added to the rim will interfere with the trailing arm, park brake bracket, sway bar, spring end and inside fender wall. Nice thing about 17" and 18" diameter wheels is that the trailing arm bends inwards so the rim widths can be wider with few or no additional mods.

The Money Pit

Here's what I am working with now. The 295/55 15 drag radials on the car going on ten years now, no clearance issues at all, but they really should be on a 10 inch wheel, not the 9 inch that I have. I have the sway bar, frame and T arm clearances as a guess using my calibrated fingers, at about 1/2 inch everywhere it's close. The thinking is that the tire will stay right where it is now, but using a 10 inch wheel with 1/2 inch deeper backset, the center of the tire ( the wheel) will expand, eliminating the pinched look, but not moving the tire at all.

resdoggie

I'm thinking the section width of the tire will remain about the same on a wider rim so that would mean the tire will also move in about 1/2" inward.

The Money Pit

Let me clarify. I add 1/2 inch more backset, so my new backset is 4.75 inches compared to my current 4.25 inch backset. I also add 1/2 inch outside....because of going to a 10 inch wheel.The wheel centerline stays in the exact same location.

The problem is the spring end. If I don't cut the spring, the end will hit the 10 inch wheel, where my 9 inch wheel clears the spring by 1/2 inch.

So,....cut spring, and just use bolts from the T arm as they are,...or try and offset the bolt using spherical rod ends like I found online. I am concerned that the bolts should be as vertical as possible, for maximum strength, and that is why I am asking what others have done.

Yes,....18 inch wheels would eliminate this headache...….

69Vett

I would get correct dia. and offset/width and avoid cutting the spring.
I do radius the spring end slightly to avoid rough cut end sticking next to tire.

v2racing

There are a lot of people running the shorter springs. VB&P sold shorter springs. I shortened my own. It does put a little angle on the bolts, but it doesn't create any problems.

Mike

Metalhead140

Your section width of the tyre will increase with the wider wheel too, rule of thumb is 3/8" for every 1/2" change in wheel width.

I agree. I shortened mine about 5/8" each side from memory (actually you just shorten one side and redrill the centre hole), haven't had any issues.

doorgunner

I inverted the bolts for a "cleaner look" (1st photo).
Before with 295 tires on 8 x 15 rims (3/8" clearance)...........









I fabricated a new main leaf 1/2" shorter on EACH end in case I installed wider tires again since the original leaf was sagging.. The bolts are "angled" but the camera exaggerates the angle.
"New leaf" (1/2" shorter on each end)..........




The shortened leaf gave me about 5/8" clearance on each end of the new leaf.

Günther-C3

At VB&P you can order a fibgerglas spring shortened each side. Just tell them.